Method of forming a cylindrical sealing body with integral diverted lantern ring for a rotary mechanical device

ABSTRACT

A bearing with an integral diverted lantern ring for installation into the seal cavity of a rotary mechanical device to provide a bearing surface and allow for flush fluid to engage the shaft closer to the motor end is provided. The bearing eliminates whip in a rotating shaft and is split to allow easy installation over an installed shaft. The bearing is substantially cylindrical with an inner bore closely approximating the outer diameter of the shaft. The diverted lantern ring includes an outer groove at the impeller end on the outer surface at a flush port and a groove on the inner surface at a location closer to the motor end. Flush fluid channels are provided between the outer groove and inner groove of the bearing. The purpose is to redirect the external flush from the impeller end on the OD to the motor end on the ID, thus repositioning the flush deposit on the sleeve, under the bearing. This allows the throttling characteristic of the close clearance bearing surface to increase.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of pending U.S. patent application Ser.No. 14/935,897, filed Nov. 9, 2015, for BEARING WITH INTEGRAL DIVERTEDLANTERN RING FOR A ROTARY MECHANICAL DEVICE, the contents of which areincorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

This invention relates to an improved bearing with an integral lanternring for a rotary mechanical device and, more particularly, to animproved bearing with the lantern ring having offset outer and innerflush holes.

Rotary mechanical devices, such as mixers and centrifugal pumps, includean impeller mounted on a shaft which is driven by an electrical motor.The shaft passes through a seal cavity or a stuffing box defined by acylindrical cavity in the device housing. The shaft is supported bybearings at the motor end, and seals are placed in the stuffing box toengage the shaft to prevent fluid from passing through the seal cavityand reaching the bearing and the motor, causing damage to both.

In mechanical pumps, chemical fluids or solvents being pumped, many ofwhich are corrosive, enter the seal cavity. Accordingly, it is importantthat appropriate packing material is placed within the seal cavity. Inaddition, fluid such as seal water is pumped into the seal cavitythrough a flush port to prevent the fluid being pumped or mixed fromtravelling along the shaft to the bearings and motor and to providelubricant to the packing. Over extended use, the pump shaft may developa whip as the bearings wear. Thus, it is highly desirable to provide asealing system that provides an effective seal and an additional bearingsurface to reduce the whip that can occur as the shaft rotates, thuscontrolling the amount of seal fluid entering an outer lantern ringgroove in the seal cavity.

While there are a wide variety of devices available for use in providingsealing in a seal cavity, it is desirable to provide a improved bearingand sealing system providing an additional bearing surface for theimpeller end of the shaft and causing a reduction in the pumped or mixedfluid entering the seal cavity to be countered by the seal fluid andpacking to provide advantages over available devices.

SUMMARY AND OBJECTS OF THE INVENTION

Generally speaking, in accordance with the invention, an improvedbearing with an integral diverted lantern ring for a rotary mechanicaldevice is provided. The bearing is a substantially rigid member with anouter lantern ring groove at one location along the bearing axis and aninner lantern ring groove at another location along the bearing axis,with channels in the bearing wall to direct seal fluid onto the shaftfrom the inner lantern ring groove. The inner bore of the bearingprovides a bearing surface for eliminating whip in the device shaft. Thebearing is split to provide easy installation over an installed deviceshaft.

The bearing prepared in accordance with the invention is substantiallyrigid and is typically manufactured of a non-ferrous metal orthermoplastic material for providing an improved bearing surface andresistance to industrial solutions. The inner bore of the bearingclosely approximates the outer diameter of the pump shaft. The externalsurface of the bearing includes a groove for receiving seal fluid withchannels to an inner groove to form an internal lantern ring. Typically,the outer lantern ring groove is located at a flush inlet port near theimpeller end of the stuffing box, and the diverted flow exits thelantern ring at the inner groove closer to the motor end. Generally, twoor more packing rings are added on the motor side of the bearing tocomplete the installation.

Accordingly, it is an object of the invention to provide an improvedbearing with an integral lantern ring to be inserted into a seal cavityof a rotary mechanical device.

Another object of the invention is to provide an improved bearing withan integral lantern ring with an outer grove at one location along thelength of the bearing and an inner or internal groove connected theretoat another location along the length of the bearing.

Still another object of the invention is to provide an improved bearingfor a rotary mechanical device having an integral lantern ring and abearing outer O-ring for improved isolation of the product being handledby the rotary device.

Yet another object of the invention is an improved bearing with anintegral diverted lantern ring for use with complementary flexiblepacking rings for use in a shaft sealing system to be inserted into theseal cavity of rotary mechanical devices.

A further object of the invention is to provide a bearing with anintegral lantern ring with an outer lantern ring groove and holes closerto the impeller end of the seal cavity and an inner lantern ring grooveand holes closer to the motor end of the seal cavity.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification and claims.

The invention comprises a product possessing the features, properties,and the relation of components which will be exemplified in the producthereinafter described and the scope of the invention will be indicatedin the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference is made to thefollowing description taken in connection with the accompanyingdrawings, in which:

FIG. 1 is a partial cross-sectional view of a typical rotary fluid pumpwith a bearing in accordance with the invention installed in the sealcavity;

FIG. 2 is an enlarged cross-sectional view of the seal cavity of thepump showing a bearing with diverted lantern ring sealing system inaccordance with the invention in place in the seal cavity;

FIG. 3 is a side elevational view of the bearing with diverted lanternring of FIG. 2 prepared in accordance with the invention;

FIG. 4 is a perspective view of the bearing of FIG. 3;

FIG. 5 is a cross-sectional view along the line 5-5 in FIG. 3;

FIG. 6 is a cross-sectional view along the line 6-6 in FIG. 3; and

FIG. 7 is a side elevational view of an embodiment of the inventionwherein the bearing of FIG. 2 includes an outer O-ring;

FIG. 8 is a perspective view of the two sections of the bearing of FIG.3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a generic form of a centrifugal pump 11 incross-section mounted on a frame 10. Pump 11 includes a centrifugalimpeller 12 driven by an electric motor 13 that drives a rotary shaft 14coupled to impeller 12. Shaft 14 is supported by a bearing housing 16and rotates to draw fluid in through an impeller inlet 17 and expel thefluid out through a radial impeller outlet 18.

Pump 11 includes a housing 19 having an inner bore 21 that defines aseal cavity or stuffing box 22 with shaft 14 passing therethrough asshown in detail in FIG. 2. Housing 19 includes an impeller opening 23through which shaft 14 passes to engage impeller 12 and also includes aflush port 25 at the impeller end of stuffing box 22 for introduction ofa flush fluid into stuffing box 22. Shaft 14 is coupled to impeller 12by a nut or fastener 24 at the end portion of shaft 14 projectingthrough impeller 12.

Pump 11 operates by drawing a fluid to be pumped into inlet 17. Duringpumping, fluid tends to migrate and be forced into seal cavity 22through opening 23. A wide variety of seals and venting configurationsare available to be placed in seal cavity 22 abutting opening 23 inorder to restrict and limit entry of pumped fluid into seal cavity 22.If fluid enters seal cavity 22 and migrates to bearings 32 a, 32 b,bearings 32 a, 32 b will be subject to substantial degradation due tothe corrosive action of the pumped fluid.

FIG. 2 is an enlarged view of seal cavity 22 with a bearing withdiverted lantern ring 31 in accordance with the invention in place. Themotor end of seal cavity 22 is defined by a gland follower 27 mounted ongland bolts 28 and secured in place by gland nuts 29.

As shown in FIG. 2, bearing 31 constructed and arranged in accordancewith the invention is positioned against the impeller end of seal cavity22. A pair of compressible sealing rings 32 a, 32 b are positioned onthe motor side of bearing 31. These elements are secured within sealcavity 22 by gland follower 27. Examples of various types of packingrings suitable for use herein are shown in U.S. Pat. Nos. 5,370,926,4,559,862, 4,431,698, 4,371,180, and 4,298,207, the contents of whichare incorporated herein by reference.

In FIG. 3, bearing 31 is shown in a side elevational view. Bearing 31 iscustom made for a particular shaft and pump. Bearing 31 is shown inperspective in FIG. 4.

Bearing 31 is a substantially cylindrical rigid member with an outersurface 33 and with an inner bore 34 closely dimensioned to the outerdimension of pump shaft 14 and fits within inner bore 21 of pump housing19. Outer surface 33 of bearing 31 is formed with an outer flush fluidgroove 36 at the impeller end at the location of flush port 25. Innerbore 34 of bearing 31 provides a bearing surface for shaft 14 when inposition as shown in FIG. 2, and this is custom dimensioned for aparticular mechanical device.

Bearing 31 is also formed with an inner flush fluid groove 37 formed ina location closer to the motor end to create a diverted lantern ring.Inner seal fluid groove 37 is formed in a position not adjacent to, thatis, not aligned with, the location of outer flush fluid groove 36. Aplurality of flush fluid holes 38 formed in outer bearing flush fluidgroove 36 are in fluid communication with flush fluid holes 45 in innergroove 37 through channels 46.

In the embodiment illustrated in FIGS. 1-3, outer lantern ring groove 36is closer to the motor end of stuffing box 22. The purpose of providingthe diverted lantern ring with holes 45 closer to the motor end is toredirect the external flush from outer groove 36 to inner groove 37 atthe motor end. This increases the throttling characteristic of the closeclearance of the bearing surface to the shaft.

In order to place bearing 31 in position in seal cavity 22, bearing 31is split along a centerline 39, as shown in FIGS. 5 and 6. Splittingbearing 31 along a diameter allows bearing 31 to be placed aboutinstalled shaft 14 and pushed into position at the impeller end of sealcavity 22. Generally, at least one or two packing rings 32 a, 32 b arepositioned on the gland side of bearing 31.

Bearing 31 split along center line 39 includes a pair of correspondingholes 41 on both halves of split bearing 31 for receiving mounting pins42 for realignment and reassembly thereof. In this construction, pins 42insure that when bearing 31 is secured about shaft 14, outer flush fluidgroove 36 and inner groove 37 are properly aligned on both sections.Outer flush fluid groove 36 is positioned to align with flush port 25formed in housing 19.

FIG. 7 illustrates an embodiment of the invention wherein a bearing withdiverted lantern ring 51 includes an outer surface 52 with an O-ring 53groove positioned in seal cavity 22. An O-ring 54 is positioned inO-ring groove 53 formed on outer surface 52 of bearing 51. O-ring 54 canbe formed of a variety of resilient materials, includingperfluoroelastomers or other resilient material compatible with thepumped fluid for providing an additional barrier to isolate the motorend of shaft 14 from fluid entering seal cavity 22. An O-ring 54provides an additional obstacle to prevent fluid from entering sealcavity 22.

Bearing 31 or 51 is custom made for a particular shaft and pump.Cross-sectional elevational views of the mating faces of bearing 31before reassembly are shown in FIGS. 6 and 7. FIG. 8 is a perspective ofthe two sections of an axially split bearing showing four extractionholes 48 at the motor end of the A section of bearing 31.

Many types of rotary equipment have the flush port close to the impellerend of the stuffing box. Almost all of these operate with heavy solids,such as mining and foods. Many pumps, such as Weir Slurry Group (WarmanPumps) pumps, GIW (Georgia Iron Works) pumps, Morris Pumps, and KrebsPumps, and mixers (vertical and horizontal) often times have the portlocated there. The theory is that in order to keep slurry out of thestuffing box, the best position is at the throat. The shortcoming withthis view is that flush pressure and volume are not equalized all theway around the lantern ring before it goes into the process solids. Byproviding a bearing with a close clearance bearing surface ahead of theexit ports of the lantern ring, the close clearance between shaft andbearing where the flush enters, forces equalization all the way around,before the flush fluid gets to the throat.

The following Example is set forth by way of illustration to helpexplain the invention, and is not intended to be limiting in any way.

Example I

A bearing with an integral diverted lantern ring in accordance with theinvention is prepared as follows. The bearing is of a given length withan A Section that is the extraction side with an inner lantern ringgroove and a B Section that is the impeller side and is chamfered withan outer lantern ring groove.

-   -   1. A piece of tube stock of a selected material is cut to a        length corresponding to the total length of Sections A and B;    -   2. The piece is then cut into an A Section and a B Section;    -   3. End holes are drilled in the mating end faces of Sections A        and B;    -   4. Pins are inserted into the holes in the mating faces to        facilitate press-fit reassembly of the Sections A and B;    -   5. The combined Sections A and B are split in half axially.    -   6. The individual sections are milled, drilled and pinned and        reassembled for final machining;    -   7. O.D and I.D. are finish turned to a specific diameter;    -   8. An inner groove is formed in Section A, and outer groove is        formed in Section B, at predetermined locations;    -   9. Aligned flush holes are drilled in the O.D and I.D groove in        each Section A and B to a predetermined depth;    -   10. Flush channels are completed by drilling into mating faces        of each section to break through and connect to existing drill        holes; and    -   11. Extraction holes are drilled into the motor end of Section        A.

In this case bearing 31 of FIG. 3 has outer diameter 33 of 9.172″ andinner diameter 34 of 7.140″ and is 2.963″ in length. The A section withinner groove 37 and extraction holes are cut to 1.482″ in length. Innergroove 37 is cut 0.250″ from the extraction end and 0.625″ wide. The Bsection outer groove 36 cut 0.375″ from the impeller end to match flushport 25 port the device. Flush holes 44 and 45 are ⅜″ in diameter andflush channels 46 are completed by drilling into the mating faces ofeach section.

The dimensions set forth above are representative and not limiting ofthe invention. The actual dimensions of aspects of bearings to beprepared and installed according to the invention will vary according tothe particular application.

Bearings 31 and 51 are substantially rigid and formed of materials whichwill not be attacked or destroyed by corrosive fluids being transportedby pump 11. Preferred materials of construction include non-ferrousmaterials, molybdenum/-carbon or glass filled thermoplastic material,such as polytetrafluoroethylene (PTFE) or other suitable plasticmaterial. Materials are selected that can provide a suitable bearingsurface and are resistant to most industrial solutions. Suitable bearingmaterials are those that provide suitable chemical, temperature,compressive strength, flexural strength and wear characteristics and canbe appropriately machined to yield the desired bearing dimensions andtolerances. Such bearing materials include, but are not limited to,polymers, including polyphenylene sulfides, polyimidizoles,polyamideimides, polybenzylimidizoles, PEEK polymers obtained bystep-growth polymerization by the dialkylation of bisphenolate salts,PTFE, perfluoroalkoxy, and formulations containing these polymers in amajor proportion.

Packing materials are described in the aforementioned U.S. Pat. Nos.4,298,207, 4,371,180, 4,431,698, 4,559,862, and 5,370,926, the contentsof each of which are incorporated herein by reference in their entirety.More particularly, useful materials include, but are not limited to,mechanically and/or thermally resilient component of graphite tape,expanded graphite foil, graphite fiber, carbon fiber, polybenzimidazole(PBI) fiber, PEK fiber, PEEK fiber, PFA fiber, aromatic polyamide fiber,Inconel or Monel wire, or combinations thereof. In another aspect of theinvention, the at least one packing member is a material selected fromthe group consisting of carbonized yarns, graphitized yarns, exfoliatedgraphite yarns, ceramic yarns, and glass yarns. Tension or lip sealrings may comprise the same or different components of the same ordifferent components. The packing rings or members may comprisemechanically and/or thermally components, whether individually or bycombinations thereof, i.e., corner yarns, resilient core, etc. Thedesigns and materials are chosen to resist packing consolidation.

Braided packing rings may include fibers of flax, jute, asbestos, or asynthetic material, such as polytetrafluoroethylene, which fibers areformed into yarns or strands and which are braided together about corestrands. The result is typically a packing having a square cross-sectionand herringbone weave pattern extending in an axial direction along thepacking. Typical packing members are illustrated in U.S. Pat. No.3,646,846, incorporated herein by reference.

In order to place bearing 31 in position in seal cavity 22, bearing 31is preferably split along a centerline 39. Splitting bearing 31 along adiameter allows bearing 31 to be placed about installed shaft 14 andpushed into position at the impeller end of seal cavity 22. Generally,at least one or two packing rings 32 a, 32 b are positioned on the glandside of bearing 31.

Bearing 31 split along center line 39 includes a pair of correspondingholes 42 on both halves of split bearing 31 for receiving mounting pins42 for realignment and reassembly of bearing 31. In this construction,pins 42 insure that when bearing 31 is secured about shaft 14, outerseal water groove 36 and inner groove 37 are properly aligned on bothsections. Outer seal water groove 36 is dimensioned and positioned toalign with a flush port 25 formed in housing 19.

It can readily be seen that the bearing with integral diverted lanternrings as part of a cylindrical seal and seal system constructed inaccordance with the invention can be easily installed in a conventionalrotary impeller pump with pins to guarantee alignment of the seal uponinstallation. This configuration allows seal fluid to contact the shaftcloser to the motor end. Generally, two packing rings or more are addedto complete installation of an effective sealing system. When in place,the bearing will support the impeller end of the pump shaft, providingan additional bearing surface to aid in eliminating the whip commonlyfound in pump and other rotary equipment shafts. Since the clearancebetween the pump shaft and the bearing is relatively small, flush fluidentering the lantern ring groove would be considerably throttled,thereby minimizing the quantity of seal water flushing and lubricatingthe bearing and finally entering into and diluting the product beingpumped.

It will thus be seen that the object set forth above, among those madeapparent from the preceding description are efficiently attained and,since certain changes may be made in the device set forth withoutdeparting from the spirit and scope of the invention, it is intendedthat all matter contained in the above description and shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention, which, as amatter of language, may be said to fall there between.

What is claimed is:
 1. A method for manufacturing a sealing body havinga total length of a Section A and a Section B with an integral divertedlantern ring with an external lantern ring groove and holes at onelocation along the axis of the body in the Section A and an internallantern ring groove at a different location on the axis in the SectionB, comprising: providing a section of a substantially cylindrical tubestock of a selected material of a length corresponding to the totallength of the Section A and the Section B; cutting the length of thetube stock into the Section A and the Section B with mating end facesalong the cut; drilling end holes in the mating end faces of the SectionA and the Section B, respectively; inserting pins into the holes in themating faces to facilitate press-fit reassembly of the Section A and theSection B; splitting the combined the Section A and the Section B inhalf axially; milling, drilling, and pinning the Section A and theSection B; reassembling the Section A and the Section B for finalmachining; finish turning the O.D. and I.D. of the reassembled sectionsto a specific diameter; forming an inner groove in the Section A and anouter groove in the Section B at predetermined locations; drillingaligned flush holes in the O.D. and I.D. grooves in each of the SectionA and the Section B to a predetermined depth of the sidewall; drillingflush channels into the mating faces of each of the Section A and theSection B to break through and connect to the existing flush holes; andplacing the mating faces together to form the substantially cylindricalsealing body with an integral diverted lantern ring.
 2. The method ofclaim 1, further including the step of drilling extraction holes intothe motor end of the Section A or the Section B.
 3. The method of claim1, wherein the substantially rigid cylindrical body is formed of abearing grade material and the body is dimensioned to provide a bearingsurface for the shaft.
 4. The method of claim 1, including forming theouter groove closer to the output end.
 5. The method of claim 1,including the step of splitting the body axially to facilitateinstallation over an installed shaft.
 6. The method of claim 1,including forming the body from a non-ferrous metal material.
 7. Themethod of claim 1, including forming the body from a molybdenum andcarbon filled thermoplastic material.
 8. The method of claim 1,including making the width of the outer groove at the output endnarrower than the length of cylindrical outer wall at the motor end. 9.The method of claim 1, including making the width of the inner groove atthe motor end narrower than the length of the cylindrical outer wall atthe output end.
 10. The method of claim 3, including formingcorresponding alignment holes in each side of the split sealing body andinserting alignment pins in the alignment holes.
 11. The method of claim1, including forming an O-ring groove on the outer surface of thecylindrical body between the outer groove and the output end, andinstalling an O-ring in the O-ring groove.